1. Field of the Invention
The invention is directed generally to an improved prelubricator and pressurized lubricant reservoir assembly for use with machinery requiring lubrication, such as an internal combustion engine.
2. Description of the Prior Art
The use of preoiling devices and oil reservoirs or accumulators of various designs in conjunction with internal combustion engines is generally well known. It has long been an acknowledged fact that a great deal of engine wear occurs as a result of "cold start scuffing", i.e., the starting of an engine after it has been idle for a period of time sufficient to allow its lubricating oil to drain into the engine's oil pan and crankcase, thus leaving many vital engine parts with no lubricant protection until the engine has been started and the oil pressure brought up to an acceptable level by the oil pump. Various preoiling devices have been designed, all having the purpose of providing oil pressure to the engine prior to start up. However, a number of these preoilers have been bulky and complex, cumbersome, have often required separate pumps, have utilized complex valving arrangements, have been difficult to service, and have generally been unacceptable for use in commercial passenger vehicles. Examples of such devices are disclosed in U.S. Pat. Nos. 3,422,807 and 3,722,623 to Waldecker, and 3,556,070 and 3,583,525 to Holcomb.
My prior U.S. Pat. No. 4,094,293 issued June 13, 1978 discloses an engine preoiler and lubricant reservoir assembly comprising a hollow cylinder divided into two chambers by a slidable piston which overcomes the aforementioned disadvantages of the prior art. Although this preoiler and reservoir assembly is a significant improvement over previous devices, the use of a slidable piston between the oil and the air in the reservoir cylinder has certain disadvantages. For example, during cold weather, the force required to break the seal between the piston rings and the interior cylinder wall increases significantly. Thus, when ambient air temperature decreases, a condition when preoiling of an engine is important, the effectiveness of the preoiler is decreased and its lubricant discharge rate is slowed. Also, the assembly uses a number of moving parts, which periodically wear out and must be replaced, and regular maintenance of the assembly is required. Such a piston-type reservoir is also expensive and complex to manufacture, and is of considerable weight, which affects fuel economy.